After trying a number of different solutions for our energetic, athletic, wriggle out of anything Irish Setter, we came across Perfect fit. We havea combination of a small, a medium and a large part, which give us a perfect fit. We had had to replace the front section twice - one per year - as we use the front ring when she is running on a long extening lead . This gets a lot of punishment. When we tried just using the top ring she was able to pull backwards out of it and escape, but never when we use the front ring. When we mwalk her on a normal lead using front and top rings, she walks perfectly for us, and this had been the problem we were trying to solve. We find the Perfect Fit harness to fits perfecty, is comfortamtable and easy to put on and off.